python-checkio/ElectronicStation/largest-histogram.py

34 lines
1.2 KiB
Python

def largest_histogram(histogram):
stack = list()
max_area = 0
index = 0
while index < len(histogram):
if (not stack) or (histogram[stack[-1]] <= histogram[index]):
stack.append(index)
index += 1
else:
top_of_stack = stack.pop()
area = (histogram[top_of_stack] *
((index - stack[-1] - 1)
if stack else index))
max_area = max(max_area, area)
while stack:
top_of_stack = stack.pop()
area = (histogram[top_of_stack] *
((index - stack[-1] - 1)
if stack else index))
max_area = max(max_area, area)
return max_area
if __name__ == "__main__":
# These "asserts" using only for self-checking and not necessary for auto-testing
assert largest_histogram([5]) == 5, "one is always the biggest"
assert largest_histogram([5, 3]) == 6, "two are smallest X 2"
assert largest_histogram([1, 1, 4, 1]) == 4, "vertical"
assert largest_histogram([1, 1, 3, 1]) == 4, "horizontal"
assert largest_histogram([2, 1, 4, 5, 1, 3, 3]) == 8, "complex"
print("Done! Go check it!")